The Characteristics of Phylum Cnidaria. Phylum Cnidaria Class Anthozoa Class Hydrozoa Class...
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Transcript of The Characteristics of Phylum Cnidaria. Phylum Cnidaria Class Anthozoa Class Hydrozoa Class...
Phylum CnidariaPhylum Cnidaria
Class Anthozoa
Class Hydrozoa
Class Scyphozoa
Class Cubozoa
CoralsAnemones
HydraPortuguese Man-Of-War
Stinging LimuFire Coral
True jellyfish Box jelliesSea wasps
Characteristics of Phylum CnidariaCharacteristics of Phylum Cnidaria
• radial symmetry• blind sac gut (= coelenteron or gastrovascular cavity)• diploblastic with mesoglea• polyp and medusa body forms• nematocysts (= specialized stinging capsules)• nerve net• lack excretory, circulatory & respiratory systems• complex life cycle• many colonial forms exhibiting polymorphism
• radial symmetry• blind sac gut (= coelenteron or gastrovascular cavity)• diploblastic with mesoglea• polyp and medusa body forms• nematocysts (= specialized stinging capsules)• nerve net• lack excretory, circulatory & respiratory systems• complex life cycle• many colonial forms exhibiting polymorphism
Radial SymmetryRadial SymmetryJellyfishJellyfish
Phylum CnidariaPhylum CnidariaJellyfishJellyfish
Phylum CnidariaPhylum Cnidaria
Medusa
Diploblastic- two germ layersDiploblastic- two germ layersDiploblastic- two germ layersDiploblastic- two germ layersPhylum CnidariaPhylum CnidariaPhylum CnidariaPhylum Cnidaria
More NematocystsMore NematocystsMore NematocystsMore Nematocysts
http://www.youtube.com/watch?NR=1&v=-Tp38DUjUnM&feature=endscreen
Diffusion Across the Body WallDiffusion Across the Body WallDiffusion Across the Body WallDiffusion Across the Body Wall
Circulation in a Circulation in a Moon JellyfishMoon JellyfishCirculation in a Circulation in a Moon JellyfishMoon Jellyfish
• polyps and medusa stage, although polyp stage is dominant.
• gut cavity of polyp is simple, lacking a pharynx and not divided by mesenteries.
• tetramerous (four-part) radial symmetry.
• gonads are ectodermal (found in the epidermis).
• medusa stage may possess specialized balance organs called statocysts and photosensitive organs called ocelli.
• solitary or colonials; some colonial forms highly polymorphic.
• includes hydroids (“stinging limu”), fire coral, pink coral, and siphonophores.
Class Hydrozoa(Gr. hydra, water serpent)
• medusae stage dominate.
• polyp stage (scyphistoma) goes through strobilization to produce young medusa.
• bell margin lacks a velum.
• tetramerous (= four-part) radial symmetry.
• gut divided into a complex system of radial canals.
• some with a simple single mouth, but many with thousands of microscopic “mouths” at the ends of oral arms.
• gonads endodermal (found in the gastrodermis).
• specialized sense organs called rhopalia with ocelli & statocysts .
• includes some 200 marine species.
• "true" sea jellies.
Class Scyphozoa(Gr. skyphos, cup)
• medusae dominate stage.
• polyp stage develops directly into medusa.
• bell margin with a velarium.
• tetramerous (= four-part) radial symmetry; bell cube-shaped with tentacles arising from each corner.
• gonads endodermal (found in the gastrodermis).
• specialized sense organs called rhopalia with ocelli & statocysts .
• includes some 15 marine species.
• includes box jellies and sea wasps.
Class Cubozoa(Gr. kybos, a cube)
• Polyp stage only
• Blind sac gut
• mesenteries radiate inwards from the body wall
• gonads endodermal, borne on the mesenteries
• hexamerous (6-part) or octamerous (8-part) radial symmetry or biradial
• sea anemones, “true” stony corals, sea fans, sea pens, organ pipe coral, precious black coral, & zoanthids
(Gr. anthos, flower)
Class Anthozoa
Subclass HexacoralliaOrder Zoanthidae
• No hard skeleton• May be tough and leathery• Shallow water forms• Encrusting forms• Some with zooxanthellae• Polyp stage only
Subclass HexacoralliaOrder Scleractinia
“True” Stony CoralsHermatypic- reef building, zooxanthellae
Common species:• Acroporidae- table• Acroporidea- rice • Agariciidae- flat lobe, corrugated• Faviidae- crust, ocellated• Fungiidae- humpback, mushroom• Pocilloporidae- lace, antler, cauliflower• Poritidae- finger, lobe, plate
“True” Stony Coralslobe
finger
mushroom
Porites rus